Wireless networks are being widely deployed due to the convenience of tether-less communications. The wireless networks are operable to support fixed or mobile/nomadic applications. The wireless network can be deployed indoors and outdoors. Further, such wireless networks can range from optical or near optical spectrum bands to radio frequencies from terahertz to megahertz bands.
Wireless networks have been witnessing increasing capacity/data rates, coverage and seamless connectivity. Wireless networks span wide area including satellite networks to wide area mobile networks to local area WiFi (Wireless Fidelity) to restricted (room) or personal area networks. These WiFi networks offer a low cost way of achieving high data throughput rates. Some of these networks, such as cellular, use licensed frequency bands, while others operate in unlicensed bands. More recently, more complex ways of band sharing have also been introduced. Due to the nature of wireless propagation and the complex protocols used in transmission and access, wireless networks often show a range of problems from simple inability to connect to the network to poor throughput performance.
Such problems are particularly evident in WiFi networks that use Carrier Sense, Multiple Access with Collision avoidance (CSMA/CA) mechanisms to regulate transmissions. Briefly, each wireless network end device detects if the medium is being used; if so, the end device waits a random amount of time before trying to transmit again. This method of contending for the medium is simple, intrinsically fair, and requires no central scheduling. However, in the case of densely deployed WiFi networks, this method of communication has a number of shortcomings, which include co-located WiFi devices contending for the medium back-off to one another, leading to wasted time when the channel is idle. Further, co-located WiFi devices that pick the same back-off time cause packets to collide over-the-air, leading to packet loss and reduced throughput. Further, end device vendors implement proprietary algorithms (e.g., for roaming) that lead to sub-optimal network performance. Further, end devices expose limited control (e.g., to schedule transmissions) for the network to optimize their performance. Further, legacy (802.11a/b/g) end devices reduce overall network throughput because they use much lower speeds and hence occupy the medium for longer time periods. Further, since WiFi uses unlicensed bands shared by other non-WiFi devices which do not follow WiFi protocols, they can cause increased contention and packet loss in WiFi networks. A number of anomalies can result in wireless networks that can be hard to detect, difficult diagnose and complex to fix. Such anomalies can range for inability to connect or reconnect, poor or intermittent throughput, which can cause a poor user experience. Poor user experience increases operations cost, poor customer or user satisfaction. Other types of wireless networks, for example, cellular networks, Zigbee networks, Bluetooth networks, infrared networks, optical communication networks, etc., are also prone to connectivity and performance failures including total breakdown (non-operation) of a network node.
Further, the location and other installation related parameters of the fixed network nodes (or at least of the antenna) such as access points and base stations need to be chosen carefully so as to maximize coverage and throughput performance of the network. This often requires in-situ measurements of radio link parameters to ascertain which installation parameter choices maximizes network performance. Since such nodes (antennas) are often located outdoors on towers, roof tops or indoors near roof ceilings, these locations are hard or hazardous to access for human operators.
It is desirable to have systems, methods and apparatuses for estimating capacity of at least one stream of a wireless link.